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Finding the Fourth Proportional to 78.76, 118.10 and 64.28

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Solution

The fourth proportional to 78.76, 118.10 and 64.28 is: 96.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.76 : 118.10 = 64.28 : x
  2. Step 2: Convert to fraction form
    78.76/118.10 = 64.28/x
  3. Step 3: Cross multiply
    78.76x = 118.10 × 64.28
  4. Step 4: Simplify right side
    78.76x = 7,591.47
  5. Step 5: Solve for x
    x = 7,591.47/78.76
  6. Step 6: Final answer
    x = 96.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.